Non-profit and public hospitals may promulgate reasonable rules fixing the standards of those who may practice therein and limiting or fixing reasonable fees for services to be rendered, including medical or surgical, and may arrange with duly licensed physicians and surgeons to provide these services in the hospital. Such services so rendered do not constitute the practice of medicine. A private corporation is prohibited from practicing medicine, and employment by a corporation of a physician or surgeon to treat the ill in order that the corporation may profit therefrom is prohibited by the laws of North Carolina.